PID controlled pellet fed barbeque
Learning how to barbeque can be an intimidating and a difficult process, taking years to master, leaving novice cooks disappointed with burnt uncooked meat. Today, there are PID (Proportional Integral Derivative) controllers that allow novice cooks to barbeque meat at the right temperature for long periods of time, removing the guess work that results in professionally cooked barbeque. However, many of the Proportional Integral Derivative (PID) controllers for barbeques are expensive and most controllers are kept a mystery, understandably to protect their proprietary information from competitors. This paper will design a barbeque with a PID controller using an Empirical Testing approach that will be tuned to one temperature at 250 °F. Data will be gathered at five different temperature ranges at 200, 225, 250, 275, and 300 °F to measure how robust the PID controller is. Also, opening the barbeque lid will act as a disturbance that will be measured and addressed in the following chapters. Only a specific cut of meat and size was used for testing, since introducing different types of meats can change the system, resulting in unreliable data for tuning the PID controller. Finally, the theory of the PID controller will be discussed and the designed barbeque will show the implementation of a PID controller for a practical application that will ultimately make barbequing an easier process. The controllability of the barbeque depends on the complexity of the system. After, many months of testing, the data showed that the system is very complex and slow to respond to disturbances. However, after tuning the PID controller with the correct coefficients, the barbeque is stable at a reference point of 250 °F. The barbeque can be operated up to 5 hours before the igniter chamber needs to be emptied. This allows the system to barbeque any meat that can fit and requires little effort to operate. Igniting the pellets and preheating the barbeque to 200 °F, is a manual 8-10 minute process but after the warm up process the barbeque is completely autonomous. Allowing the user to wait until the internal temperature is cooked to the right temperature. Future updates will improve the run time and stability and more reference points. The final design is an outstanding launching point for the future of barbequing.